LA-ICP-MS U-Pb Ages of Detrital Zircons from the Neoproterozoic Chang’an Formation in Central Hunan and Its Geological Implicatons
详细信息
- 责任者：Du Qiuding (Institute of Geology and Mineral Resources ; China Geological Survey ; Chengdu 610082 ; China) ; Wang Zhengjiang
- 刊名：Geological Review
- 出版年：2013
- 卷期：59(2)
- 关键词：铀—铅计时 ; U-Pb dating ; 新元古代 ; Neoproterozoic Era ; 湖南 ; Hunan Province
- 页码：p.334-344
- 图表：illus., 1 table, 59 refs.
- 分类号：1200
- issnNo：ISSN0371-5736
- isbnNo：CN11-1952/P
摘要
The Yangtze Block in South China is one of the important regions in the world where the Neoproterozoic glacial sediments are well developed and well studied. In this paper, we report and analyse the LA-ICP-MS U-Pb ages of detrital Zircon grains from the Jiangkou Group in the Central Hunan, Southeastern Yangtze Block. Together with compilations of all available high precision zircon U–Pb data on tuff beds in the Nanhua Basin, our work demonstrates that the Cryogenian deposition in South China had three depositional cycles at 831～720 Ma, 1005～842 Ma and 2500～1933 Ma. The dominant age group can be further divided into two sub-groups with weighted mean age of 769 and 828 Ma, the youngest grain gives a 206Pb/238U age of 720 Ma. The youngest age population gives a mean 206Pb/238U age of 769 Ma that constrains the onset time of the Sturtian (Chang’an) glaciation to < 770 Ma.The largest age group 750～830 Ma from the Cryogenian sedimentary rocks maybe compare global episodic continental growth and reworking events with possibly coupled Rodinia supercontinent break up. The late Paleoproterozoic (1.9～2.5 Ga) thus appears to have witnessed significant of continental reworking in central Hunan Province.
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